The world is watching as Canada becomes one of the first countries to legalize recreational cannabis, and there's still much we don't know about how this huge social change will affect our lives. In this webinar, Dr. Chris Wilkes, MD, from UCalgary's Cumming School of Medicine reviews what the research to date tells us about the impact of cannabis on the brain, and what needs further study. Dr. Fiona Clement, PhD, whose team compiled the Cannabis evidence series for the Alberta provincial government, looks at the factors informing government policy, including evidence from other jurisdictions that have legalized marijuana. Watch the full webinar recording at https://go.ucalgary.ca/2018-07-11URNAP-WhatdoeslegalizedcannabismeanforCanadians_LPRegistration.html

1. What does legalized
cannabis mean for
Canadians?
Dr. Fiona Clement, PhD, Associate Professor
Dr. Chris Wilkes, MD, Professor
Cumming School of Medicine
July 11, 2018

2. • Associate Professor, Cumming
School of Medicine
• Director, Health Technology
Assessment Unit in the
O’Brien Institute for Public
Health
• Research interests include
health policy development
and decision-making
• Twitter @FionaHTA
Dr. Fiona Clement, PhD
2

3. • Professor, Cumming School of
Medicine, Departments of
Paediatrics and Psychiatry
• Alberta Health Services
Division Head for Child and
Adolescent Psychiatry and
Outpatient Section Chief for
Child and Adolescent Mental
Health Addictions
Dr. Chris Wilkes, MD
3

4. How did we get here?
4

5. Canadian History
5
1923:
Prohibition
of cannabis
1961: Minimum
penalty of 6
months removed
and maximum
penalty of 7
years initiated
1972: Le Dain
Report
recommends
decriminializing
cannabis, no
action was taken
1994:
Supreme Court
overturns
prohibited
distribution of
literature on illicit
drug use, Bill C-8
2001:
Medical cannabis

6. The Policy process
Evidence
Broad
Consultation
Tabled
framework
Legislation
Federal
Provincial

7. Provincial policy priorities
•Keep cannabis out of the hands of
children and youth
•Protect public health
•Promote safety on roads, in
workplaces and in public spaces
•Limit the illegal cannabis market

8. Provincial policy priorities
•Keep cannabis out of the hands of
children and youth
•Protect public health
•Promote safety on roads, in
workplaces and in public spaces
•Limit the illegal cannabis market

9. Provincial policy priorities
• Promote responsible use for all
those who choose to partake
•Protect public health
•Promote safety on roads, in
workplaces and in public spaces
•Limit the illegal cannabis market

10. Global picture

11. Canadian rates of use

12. What do we expect?

13. Use compared to other substances

14. Risk of dependency
14

15. Role in substance use

16. Final thoughts
• Living through a large social change
• Learning, nimble, responsive policy environment is
needed
• Well-positioned to lead the country

17. Marijuana and the developing brain

18. Cannabis/marijuana
• Marijuana, when smoked or inhaled, has an effect
within minutes that lasts 2 to 3 hours
• If marijuana is eaten, it can take 2 hours for the effect
to be felt – lasting up to 8 hours
• THC – euphoria, sociability and insightfulness

19. Cannabis/marijuana
Two receptors:
CB1 – Neocortex, Basal Ganglia, hippocampus and
presynaptically on GABAergic with glutamatergic
neurons.
CB2 – Immune cells, peripheral tissue brain stem and
cerebellum

20. When THC is administered to healthy
volunteers:
Impairs learning,
attention and
memory in a
dose response
manner
Doubles risk of
traffic
accidents
Short lived
psychotic
symptoms;
paranoia,
hallucinations

21. 3 populations at risk for THC are:
Pregnant women
Adolescents and youth under 25 years
Those people at risk for psychosis

22. Marijuana and pregnancy
1. Ottawa Prenatal Prospective Study (1978) - middle
class, Caucasian families
2. Maternal Health Practice and Child Development
(1982) - Pittsburgh, USA – lower socio-economic
African American women
3. Generation R Study (Netherlands) – multi-ethnic
cohort of higher socio economic class (2002)

23. Marijuana and pregnancy
Compared to those who didn’t use marijuana, the 3 studies indicate
that with heavy marijuana prenatal exposure:
• Adverse effects by 18 months of age with increased aggression and
impulsiveness
• At 6 years evidence of cognitive dysfunction, ADHD, requiring
educational remediation
• By 10-14 years, increased rates of anxiety and depression
• By 14 years of age increased rates of smoking and substance abuse

24. Marijuana and pregnancy
This is a public health issue if 10-30% of pregnant mothers use
marijuana
Marijuana perceived to be low risk but THC in 1980 = 4%
In 2008 THC increased to 10%
In 2016 THC increased to 28%

25. Marijuana & adolescents
Research in adolescent brain development shows this is a
vulnerable period especially for the prefrontal cortex:
• Problem solving
• Flexibility
• Adaptability and
• Frustration tolerance

27. Marijuana & IQ
• Dunedin Cohort study – decline of IQ of 6 points
between ages 13 – 38 years who had cannabis use
disorder
• Other studies did not replicate this but showed
worsening verbal memory but normal processing
speed
• Cannabis users with high CBD showed no cognitive
impairment

28. Effects of marijuana on mental health
patients
Patients with severe and persistent mental illness like paranoid
schizophrenia or severe bipolar disorder experience a
worsening of symptoms and develop poor compliance with
medications especially high potency THC because it:
• Increases euphoria, time distortion and perceptual changes
• Decreases motivation and psycho motor performance
• Negatively impacts parts of the brain that regulate emotions,
stress response, verbal memory and learning

29. A meta-analysis of 12 studies found that the more
extensive the cannabis use –
the greater the risk of psychosis.
Odds ratio of 4 compared to the non-users
Marconi et al, 2016
Cannabis & psychosis

30. People using high potency cannabis
on a daily basis were 5x more likely than non users to
suffer from a psychotic disorder
Di Forti et al, Lancet 2015
Cannabis & psychosis

31. Role of cannabis / marijuana
• Cannabinoid receptors modulate pain
• CBD – for multiple sclerosis and epilepsy
• Smoked THC helps HIV-associated neuropathy and
chronic neuropathic pain.
• No Psychiatric Evidence for First Line treatment,
American Psychiatric Association 2013

32. Conclusion
Canadian Medical Association (80,000 members)
recommends legalization and regulation of marijuana
• Limiting the potency and the amount one person can
buy (especially between 21-25 year olds)
• Phase in an educational period before April 2017

33. Conclusion
• Increase more mental health and substance abuse
services
• Reduce the perception of safety for marijuana use in
adolescents, pregnant moms and those at risk for
psychosis
• Recognize it does have a role for some PTSD, cancer
and chronic pain management